Premier Li Keqiang called for a South China Sea of "peace and friendship", during a meeting with the heads of the 10-member Association of Southeast Asian Nations (ASEAN) in the oil-flush sultanate of Brunei.

"A peaceful South China Sea is a blessing for all. We need to work together to make the South China Sea a sea of peace, friendship and cooperation," Li said.

Li took the baton from President Xi Jinping, who underlined Chinese power by occupying centre-stage in previous days at an Asia-Pacific summit in Bali with Obama stuck at home due to the US government shutdown.

Some ASEAN members who hold various claims to the South China Sea have voiced increasing alarm at perceived provocative acts by Beijing in asserting its claims in the strategic body of water.

China has sought to portray a friendlier face more recently, dangling lucrative trade promises around the region - while holding its ground on its claims to most of the South China Sea.

In sharp contrast to the often icy tone China takes with perceived rivals like the United States and Japan, Li showered his ASEAN counterparts with pledges of friendship and deeper economic integration.

Smiling and energetic, he called for the two sides to ramp up efforts to more than double China-ASEAN trade to $1 trillion by 2020, from about $400 billion last year.

Obama had said earlier in the year he planned during the Brunei gathering to lend his presidential prestige to calls for a speedy agreement between China and ASEAN on a code of conduct at sea to avoid accidental conflict.

However, as he did in Bali, Obama's top diplomat John Kerry was in Brunei instead to show support for America's Asian allies.

The two days of revolving-door talks in Brunei include ASEAN, the United States, Japan, and South Korea and several other regional players.

China has succeeded in lowering temperatures by agreeing recently to join with ASEAN in initial talks toward a code of conduct.